--- a/devtools/__init__.py	Tue May 03 13:57:18 2011 +0200
+++ b/devtools/__init__.py	Tue May 03 17:43:53 2011 +0200
@@ -28,15 +28,17 @@
 import pickle
 import glob
 import warnings
+import hashlib
 from datetime import timedelta
 from os.path import (abspath, join, exists, basename, dirname, normpath, split,
                      isfile, isabs, splitext, isdir, expanduser)
 from functools import partial
-import hashlib
 
 from logilab.common.date import strptime
 from logilab.common.decorators import cached, clear_cache
-from cubicweb import CW_SOFTWARE_ROOT, ConfigurationError, schema, cwconfig, BadConnectionId
+
+from cubicweb import ConfigurationError, ExecutionError, BadConnectionId
+from cubicweb import CW_SOFTWARE_ROOT, schema, cwconfig
 from cubicweb.server.serverconfig import ServerConfiguration
 from cubicweb.etwist.twconfig import TwistedConfiguration
 
@@ -197,7 +199,10 @@
         directory from wich tests are launched or by specifying an alternative
         sources file using self.sourcefile.
         """
-        sources = super(TestServerConfiguration, self).sources()
+        try:
+            sources = super(TestServerConfiguration, self).sources()
+        except ExecutionError:
+            sources = {}
         if not sources:
             sources = DEFAULT_SOURCES
         if 'admin' not in sources:

--- a/server/serverconfig.py	Tue May 03 13:57:18 2011 +0200
+++ b/server/serverconfig.py	Tue May 03 17:43:53 2011 +0200
@@ -255,7 +255,7 @@
     # configuration file (#16102)
     @cached
     def read_sources_file(self):
-        return read_config(self.sources_file())
+        return read_config(self.sources_file(), raise_if_unreadable=True)
 
     def sources(self):
         """return a dictionnaries containing sources definitions indexed by

--- a/toolsutils.py	Tue May 03 13:57:18 2011 +0200
+++ b/toolsutils.py	Tue May 03 17:43:53 2011 +0200
@@ -159,15 +159,11 @@
         print '-> set permissions to 0600 for %s' % filepath
     chmod(filepath, 0600)
 
-def read_config(config_file):
-    """read the instance configuration from a file and return it as a
-    dictionnary
-
-    :type config_file: str
-    :param config_file: path to the configuration file
-
-    :rtype: dict
-    :return: a dictionary with specified values associated to option names
+def read_config(config_file, raise_if_unreadable=False):
+    """read some simple configuration from `config_file` and return it as a
+    dictionary. If `raise_if_unreadable` is false (the default), an empty
+    dictionary will be returned if the file is inexistant or unreadable, else
+    :exc:`ExecutionError` will be raised.
     """
     from logilab.common.fileutils import lines
     config = current = {}
@@ -190,8 +186,12 @@
             value = value.strip()
             current[option] = value or None
     except IOError, ex:
-        warning('missing or non readable configuration file %s (%s)',
-                config_file, ex)
+        if raise_if_unreadable:
+            raise ExecutionError('%s. Are you logged with the correct user '
+                                 'to use this instance?' % ex)
+        else:
+            warning('missing or non readable configuration file %s (%s)',
+                    config_file, ex)
     return config